JP5726366B2 - Printed circuit boards and diplexer circuits - Google Patents

Description

  The present invention relates to a printed circuit board for forming a diplexer circuit, and more particularly, but not exclusively, to a diplexer circuit of a base station transceiver device of a mobile communication system.

  Modern base station transceivers are operated with high efficiency to provide high data rate and quality services to mobile communication system users while keeping power consumption and radiated power as low as possible. It is necessary to Therefore, power amplifiers (abbreviated PA) and low-noise amplifiers (abbreviated LNA) (which builds a base station high frequency (abbreviated HF) front end) should receive as little noise and interference as possible. . One possible source of noise and interference is connections or crosstalk that can occur in the transmitter branch and PA and in the receiver branch and LNA through commonly used antennas. That is, part of the transmission signal may occur in the reception branch. Therefore, each filter circuit can be used to reduce such crosstalk.

  An example of such a filter circuit is a so-called diplexer, which is a passive device that implements frequency domain multiplexing. The communication system can use time division duplex communication (abbreviation TDD) or frequency division duplex communication (abbreviation FDD). In TDD, transmission and reception are separated in the time domain. That is, for a predetermined time, either transmission or reception is executed by the base station transceiver. In FDD, transmission and reception are separated in the frequency domain. That is, different frequency bands are used for transmission and reception. The diplexer can be based on two bandpass filters and can separate the transmission band from the reception band in the FDD system. Two ports (eg, L and H, which are abbreviations for the low and high frequency bands) are multiplexed into a third port that connects the antenna or antenna system (eg, in the signal abbreviation S). The signals at ports L and H occupy a disjoint frequency band. Theoretically, L and H signals can coexist on port S without interfering with each other.

  Typically, the port L signal can occupy a single low frequency band and the port H signal can occupy a higher frequency band. In that situation, the diplexer may consist of a low pass filter connecting ports L and S and a high pass filter connecting ports H and S.

  Ideally, all signal power at port L is transferred to the S port, and vice versa, and all signal power at port H is transferred to port S, and vice versa. Ideally, signal separation is complete. That is, none of the low-band signals are transferred from the S port to the H port. In the real world, some power is lost and some signal power leaks to the wrong port.

  In an FDD wireless system, separation of a transmission frequency band and a reception frequency band is a very important performance requirement for a base station transmission / reception apparatus. Due to the very high sensitivity of the receiver and the relatively large output power, the separation (usually required between these two bands) may be on the order of 70, 80, 90, or 100 dB.

  Embodiments are very difficult to achieve such a degree of separation, and the physical placement of such filters can determine a significant portion of the performance of the HF front end in addition to the filter architecture. Can be based on discovery. This is especially important in active antenna array systems. This is because the level of integration required for the device is high. That is, the TX filter and RX filter are placed very close together, again causing coupling between devices and reducing isolation.

  Embodiments include a printed circuit board (abbreviated PCB) to form a diplexer circuit that includes a first connector for connecting a first filter and a second connector for connecting a second filter. Provided, the first connector and the second connector are located on both sides of the printed circuit board. Such an embodiment allows two filters to be placed on either side of the PCB. In addition, it has been found that separation or attenuation of one PCB to the other can simultaneously enable high integration levels and high isolation levels. In other words, when two filter circuits are arranged on both sides of the PCB, they can be reliably separated at the same time while being close to each other, so that crosstalk can be suppressed to a considerably high degree.

  The term “connector” is to be understood as an interconnect or as a means for attaching an electronic device (ie a first or second filter). Such a connector can be implemented as a solder-patch that can provide mechanical and electrical support for the filter. The connector can allow a filter to be attached to the front and back of the PCB. Here, the PCB is between the connectors. In embodiments, a solder patch can be used to attach the filter and connect the filter housing to a specific voltage or reference potential. For example, the filter housing can be bonded to a solder patch and simultaneously connected to ground potential. Embodiments can also include a method for manufacturing a PCB with a first connector attached to the first side of the PCB and a second connector attached to the second side of the PCB. . The connectors can be connected to each other through the PCB or to a buried ground plane in the PCB. Further, embodiments can include a method for manufacturing a diplexer circuit. Such a method can include attaching a first filter to the first connector and attaching a second filter to the second connector of the PCB. These steps can include electrically connecting the first filter and the second filter to each other using a buried ground plane and / or using a reference or ground potential.

  In an embodiment, therefore, the printed circuit board can be adapted to form a diplexer of the base station transceiver, the first filter corresponding to the transmission signal filter and the second filter corresponding to the reception signal filter. . The first connector can correspond to the first solder patch, and the second connector can correspond to the second solder patch. In other words, the two solder patches allow the mechanical and electrical connection of the filter to the PCB, providing a mechanically stable, electrically and reliably separated mounting of both filters in close proximity. Can be achieved.

  In a further embodiment, the printed circuit board can include two layers of non-conductive substrates and a conductive layer between the two non-conductive substrate layers. The conductive layer can function as a fringe field and leakage current shield. Thus, the conductive layer can be connected to a specific potential. For example, it can be grounded. Thus, the conductive layer can have a connector for grounding the conductive layer. Furthermore, there may be at least one connection or via between the first connector and the conductive layer. There may also be at least one connection or via between the second connector and the conductive layer. In other words, since there may be an electrical connection between the two connectors and the conductive layer, all three can be connected to a particular potential, such as ground.

  The printed circuit board may further include other conductive layers that are separated from the conductive layer by a separation layer. The conductive layer, the other conductive layer, and the separation layer may be between two non-conductive substrate layers. In other words, in some embodiments, there may be two conductive parallel layers on the substrate, which may be separated from each other, and there may be a substrate between them. Thus, in effect, there may be five layers: a first substrate, a first conductive layer, a second substrate, a second conductive layer, and a third substrate. The conductive layer and the other conductive layer, i.e., the first and second conductive layers, may be parallel and may form a waveguide structure. The waveguide structure can guide electromagnetic waves, fringing electric fields, or leakage currents away from the two filter structures, while at the same time allowing greater attenuation between the two filter structures.

  The waveguide structure can be adapted to a quarter of the wavelength of the center frequency based on the transmission band determined by the first filter and the reception band determined by the second filter. In other words, there is a specific bandwidth that the transmitted signal can have that is located around the center frequency. The waveguide structure can be geometrically configured for a particular wavelength that should increase attenuation or suppress crosstalk. This wavelength can correspond to the center frequency of the transmission band, the center frequency of the reception band, or any other intermediate frequency. Basically, in embodiments, the shape of such a structure can be adapted to the strongest interference or crosstalk, and the wavelength of the strongest interference can depend on the filter structures, their transfer function characteristics, etc. There is sex. Thus, embodiments are based on the discovery that conductive structures within a PCB can be geometrically configured for crosstalk between filter structures located on both sides of the PCB to suppress the aforementioned crosstalk. There may be.

  The conductive layer and the other conductive layer, i.e., the first and second conductive layers, can form protrusions around the connector of the first filter and the connector of the second filter. The conductive layer and the other conductive layer can be connected through additional connectors or vias under the first and second connectors, and the protrusion is at least a quarter of the wavelength from the additional connector or via. Can be extended. In general, a printed circuit board can also include any means for guiding electromagnetic waves. The means for guiding the wave can be adapted to guide the electromagnetic wave for at least a quarter of the wavelength of the wave. The printed circuit board further includes separation means for separating the first connector side from the second connector side to achieve transmission band signal attenuation greater than 70, 80, 90, or 100 dB. Can do.

  Embodiments also include the circuit board embodiment described above, a first filter connected to a first connector for filtering a transmission signal in a transmission band, and a received signal in a reception band. A diplexer circuit including a second filter connected to the second connector can be provided. The first and second filters can be further connected to the antenna using a first feed line and a second feed line, wherein the first feed line and the second feed line are: The first and second filters can be located in parallel with the printed circuit board, or the first and second filters are connected to the antenna using a common antenna port, and the printed circuit board is connected to the common antenna board. A feed connector or via is included to connect the first and second filters. The diplexer can use a printed circuit board that includes two non-conductive substrate layers and at least one conductive layer between the two non-conductive substrate layers, the conductive layers being 70, 80, 90, Or adapted to provide attenuation between the transmitted signal and the received signal of greater than 100 dB.

  With reference to the accompanying drawings, by way of example only, some other features or aspects will be described for printed circuit boards and diplexer circuits using the following non-limiting embodiments.

It is a figure which shows one Embodiment of a printed circuit board. FIG. 2 shows two embodiments of a diplexer circuit, each using one embodiment of a printed circuit board, one with a separate antenna port and the other with a common antenna port. . It is a figure which shows the connector of one Embodiment. It is a figure which shows another connector of one Embodiment. FIG. 6 illustrates another embodiment of a diplexer circuit using one embodiment of a printed circuit board with a waveguide structure. It is a figure which shows one Embodiment of a diplexer circuit. It is a figure which shows another embodiment of a diplexer circuit. FIG. 5 shows a diplexer circuit in a single housing. FIG. 5 shows a diplexer circuit in a separate housing.

  An illustrative description of embodiments is provided in detail in conjunction with the accompanying drawings. FIG. 1a includes a first connector 110 for connecting a first filter and a second connector 120 for connecting a second filter, wherein the first connector 110 and the second connector 120 are printed. One embodiment of a printed circuit board 100 for forming a diplexer circuit located on both sides of the circuit board 100 is shown. Connectors 110, 120 can allow for mechanical attachment and electrical connection of the filter on the front and back of the PCB. Further, embodiments can provide a method for manufacturing a printed circuit board 100 to form a diplexer circuit. The method includes mounting a first connector 110 for connecting a first filter to a first side of the printed circuit board 100, and connecting a second filter 122 to a second side of the printed circuit board 100. Mounting a second connector 120 for performing. The first connector 110 and the second connector 120 are located on both sides of the printed circuit board 100. In other words, the first connector 110 can be located on the front surface and the second connector 120 can be located on the back surface of the PCB 100.

  FIG. 1 b uses one embodiment of a printed circuit board 100, one with a separate antenna port or feed line 116, 126 and the other with a common antenna port 160. Two embodiments of a diplexer circuit 200 are shown. The upper embodiment of FIG. 1b will first be described. The lower embodiment of FIG. 1b has similar components except for the feed line or antenna port. Description of similar components in the embodiment below is omitted.

  The upper embodiment of FIG. 1 b shows a printed circuit board 100 with two connectors 110 and 120. The embodiment further shows an attached first filter 112 and an attached second filter 122. The dashed structure 124 of the second filter 122 shows the resonator structure, which is also assumed to be present in the first filter 110. The printed circuit board 100 can be adapted to form a base station transceiver diplexer, the first filter 112 can correspond to a transmission signal filter or a blocking filter, and the second filter 122 can be It can correspond to a received signal filter or a blocking filter. The first filter 112 and the second filter 122 can be soldered on the PCB 100. Accordingly, the first connector 110 can correspond to the first solder patch, and the second connector 120 can correspond to the second solder patch.

  As seen in the embodiment, the printed circuit board 100 includes two layers 132, 134 of a non-conductive substrate and a conductive layer 130 between the two non-conductive substrate layers 132, 134. The conductive layer can include a metal. For example, the conductive layer can include copper or aluminum. The two non-conductive layers 132, 134 can also be referred to as a first non-conductive layer 132 and a second non-conductive layer 134. The PCB 100 can include at least one connection or via 140 between the first connector 110 and the conductive layer 130. The PCB 100 can include at least one connection or via 142 between the second connector 120 and the conductive layer 130. In the embodiment shown in FIG. 1b, a plurality of such connections are shown, in which only connections 140 and 142 are referenced. Further, the conductive layer 130 can have a connector for grounding the conductive layer 130.

  In FIG. 1b, arrow 150 shows the combined current separated by conductive layer 130, which can function as a ground plane. Vias 140, 142 can ensure a connection between ground plane 130 and solder patches 110 and 120. Further, the arrow 152 indicates a fringe electric field that is also separated by the ground plane 130. The lower diagram of FIG. 1b shows a similar embodiment, but uses a common antenna port 160 instead of separate feed lines 116 and 126 as shown in the embodiment shown above. . In other words, the embodiment may provide a diplexer circuit 200 where the first and second filters 112, 122 use the first feed line 116 and the second feed line 126 to , And the first feed line 116 and the second feed line 126 are located or run parallel to the printed circuit board 100. In other embodiments, the first and second filters 112, 122 can be connected to the antenna using a common antenna port 160, and the printed circuit board 100 is connected to the common antenna port 160. Feed connectors or vias may be included to connect the first and second filters 112,122. FIG. 1b shows an embodiment in which the filters 112, 122 are located on both sides of the PCB 100, and the ground plane 130 can increase the separation and form a common (antenna) port (see the embodiment below). reference).

  Further, embodiments can provide a diplexer circuit 200 wherein the printed circuit board 100 has at least one between two non-conductive substrate layers 132, 134 and two non-conductive substrate layers 132, 134. Including a conductive layer 130, wherein the conductive layer 130 is configured to provide attenuation between the transmitted and received signals greater than 70, 80, 90, or 100 dB.

  FIG. 1c shows connectors 110, 120 as an example of one embodiment of a printed circuit board. As shown in the plane structure plane of FIG. 1c, the connectors 110, 120 may correspond to ceramic block filter connectors. In an embodiment, the connectors 110, 120 can correspond to means for attaching the filters 112, 122. On the other hand, the connectors 110, 120 can function as a means for mechanically stabilizing the filters 112, 122 on the PCB, while on the other hand they can electrically connect the filters 112, 122 to the PCB. it can. In some embodiments, the connectors 110, 120 can connect the housings of the filters 112, 122 to the conductive layer 130 using vias 140, 142. FIG. 1c shows a planar connector or soldering patch 110, 120, which includes a plurality of vias or connections to the underlying conductive layer, and in FIG. 1b, two connections or vias 140, 142. Only is referenced. The underlying conductive layer can correspond to a buried ground layer. White dots in connectors 110, 120 indicate that in embodiments, there may be multiple connections to the underlying conductive layer. Further, FIG. 1c shows a connector or solder patch 116a, 126a that can be used to connect the filters 112, 122 to the feed lines 116, 126, or antenna path as described above. The connector 105 of FIG. 1 c can function to connect to the input or output port of the filters 112, 122, ie, the TX port of the transmit filter 110 or the RX port of the receive filter 120.

  FIG. 1d shows another connector 110, 120 of one embodiment of the PCB. FIG. 1d shows the same components as the connectors 110, 120 shown in FIG. 1c, but multiple connectors are shown. FIG. 1 c illustrates planar connectors 110, 120, while FIG. 1 d illustrates a connector field or patch field comprised of a plurality of connectors 110, 120. The structure of the connectors 110, 120 may correspond to a SAW (abbreviated surface acoustic wave) filter connector, as shown in the patch field structure of FIG. 1d. The outline of the filters 112, 122 is indicated by the dashed line 107 in FIG. Filters 112, 122 can connect to a plurality of connectors 110, 120, at least some of which have vias or connections 140, 142 to conductive layer 130 that can accommodate a buried ground layer. I know it ’s good. FIG. 1d also shows the port connector or solder patch 105 and the antenna path connectors or solder patches 116a, 126a, as already described in detail above.

  Embodiments can also provide a method of manufacturing the PCB 100 with the first connector 110 attached to the first side of the PCB 100 and the second connector 120 attached to the second side of the PCB 100. Connectors 110, 120 may be connected to each other through PCB 100 or to a buried ground plane 130 in PCB 100. Furthermore, embodiments can provide a method for manufacturing the diplexer circuit 200. Such a method can include attaching the first filter 112 to the first connector 110 and attaching the second filter 122 to the second connector 120 of the PCB 100. These steps include electrically connecting the first filter 112 and the second filter 122 to each other using a buried ground plane 130 and / or using a reference or ground potential. Can do.

  FIG. 1e shows another embodiment of a diplexer circuit 200 that uses one embodiment of a printed circuit board 100 with a waveguide structure. In an embodiment, the printed circuit board 100 further includes another conductive layer 178 that is separated from the conductive layer 176 by a separation layer 172, wherein the conductive layer 176, the other conductive layer 178, and the separation layer 172 include: Between the two non-conductive substrate layers 132, 134. The conductive layer 176 can also be referred to as the first conductive layer 176 and the other conductive layer 178 can also be referred to as the second conductive layer 178. Conductive layer 176 and other conductive layers 178 may be parallel and they can form a waveguide structure. The waveguide structure can be adapted to a quarter of the wavelength of the center frequency based on the transmission band determined by the first filter 112 and the reception band determined by the second filter 122.

  In an embodiment, the conductive layer 176 and the other conductive layer 178 can form protrusions or shields around the connector 110 of the first filter 112 and the connector 120 of the second filter 122 so that they are conductive. Layer 176 and other conductive layers 178 are connected through other connectors 174 or vias 174 under the first and second connectors 110, 120, and the protrusions or shields are at least of wavelength from further connectors or vias 174. Extends a quarter. The protrusion or shield can be formed by two conductive layers 176, 178 mounted in a PCB with a gap in between, and the gap can extend up to a quarter of the wavelength.

The extent of the protrusion or waveguide structure is the distance between the dotted lines
Is also shown in FIG. FIG. 1e illustrates one embodiment that provides an improved ground plane using a ground plane structure that suppresses leakage current.

  In general, in embodiments, the printed circuit board 100 can include means for guiding electromagnetic waves, and the means for guiding waves guides the electromagnetic waves for at least a quarter of the wavelength of the waves. It can be constituted as follows. Such means correspond, for example, to the above geometric structure of the conductive layer of the PCB. In an embodiment, the PCB 100 is a separating means for separating the first connector 110 side from the second connector 120 side to achieve transmission band signal attenuation greater than 70, 80, 90, or 100 dB. Can further be included. The separating means may correspond to the conductive layer described for the above embodiments.

  The embodiment also filters one embodiment of the circuit board 100, a first filter 112 connected to the first connector 110 to filter the transmission signal in the transmission band, and a reception signal in the reception band. Therefore, the diplexer circuit 200 including the second filter 122 connected to the second connector 120 can be provided.

  In FIG. 2a, an architecture or diplexer configuration for an FDD radio implementation is shown. FIG. 2a shows the diplexer circuit 200 having a transmission path, where a PA 400 followed by the PA port 302 of the diplexer 200 is located and connected to the antenna using the antenna port 306. FIG. In the reception path, the diplexer circuit 200 is connected to the LNA 410 through the LNA port 304 from the antenna. Isolation between the PA port 302 and the LNA port 304 is achieved only by the filters 112, 122 of the diplexer circuit 200. Here, since the two filters 112, 122 are formed into a single physical entity, the coupling between the PA port 302 and the LNA port 304 is less affected by the attachment of the filters 112, 122. Absent. In an embodiment, such a structure, i.e. the structure in which the two filters 112, 122 are mounted in a single housing, can also include the PCB 100 described above, the PCB 100 correspondingly, i.e. to fit the housing. Can be configured. The PCB 100 can also provide a means for attaching additional components.

  FIG. 2b shows another embodiment of the diplexer circuit 200, showing the same components as the embodiment of FIG. 2a, but the two filters 112, 122 are separate physical entities, Embodiments utilize two antenna ports 306a and 306b with a bandpass filter configuration using a two-port antenna. In the diplexer 200 shown in FIG. 2b, the separation between the ports 302, 304 can be further increased by the separation between the two antenna ports 306a and 306b. This separation can be achieved, for example, with two orthogonal polarizations, for example in a dual-polarized dipole or patch antenna. In particular, in this configuration, the two filters 112, 122 are two separate entities, so how the two filters 112, 122 are located within the physical implementation of the radio may be critical. is there. In general, the closer they are located, the greater the coupling between devices due to leakage currents and fringing fields. This can be reduced by placing the devices apart, but this also contradicts the requirement for high physical integration. Thus, embodiments can provide the advantage that the two filters 112, 122 can be placed close together, achieving a high degree of integration through the PCB 100 separating the filters while at the same time achieving a high degree of integration, In embodiments, there may be further integrated separation or shielding means.

  In embodiments, the size and weight of the filters 112, 122 can be configured to allow them to be attached to both sides of the circuit board 100. For example, enough to be used as a surface mount device such as a ceramic block filter (abbreviated CB), SAW, or film bulk acoustic resonator filter (abbreviated FBAR: film-bulk-acoustic-resonator) Small filters can be used. For embodiments, ceramic block filters can be used, but embodiments are not limited to ceramic filter technologies, and other filter technologies can be applied.

  FIG. 3a shows a single housing 500 diplexer circuit implemented as a blocking filter, eg, a ceramic block filter. FIG. 3a shows a surface mount block diplexer in which TX and RX filters form a single physical entity and are used in a radio architecture as shown in FIG. 2a. The separation is limited by the current. The diplexer includes an upper receive band filter (RX band filter) and a lower transmission band filter (TX band filter). The diplexer includes a resonator structure 502 and a coupling structure 504. In addition, FIG. 3a shows three ports: a receive port 506, a transmit port 508, and a common antenna port 510. In addition, a plurality of signal lines 512 and PCBs 514 are shown in FIG. 3a. The dashed arrow on the right side shows the fringe field between the resonators that leads to coupling between TX port 508 and RX port 506, thus limiting the separation. On the left side of FIG. 3a, dashed arrows indicate leakage currents in the metallization of the filter surface leading to coupling between TX port 508 and RX port 506 and limiting the separation.

  Such a filter device can typically be utilized as two separate implementation devices. However, they are built into the diplexer function within a single entity. See Figure 3a. Diplexers implemented as a single entity (eg, using conventional techniques) may have the disadvantage of leakage current flowing through the same surface, so that isolation is achieved when a certain level (greater than about 60 dB) is exceeded. Is difficult. This is usually not sufficient from the standpoint of performing the separation.

  FIG. 3b shows the diplexer circuit in a separate housing, with the transmission band filter shown on the left and the reception band filter shown on the right. FIG. 3b shows two surface mount blocking filters, where the TX filter and RX filter form two separate physical entities, increasing the separation by fringing field and leakage current, Restrict use to the radio architecture as shown. FIG. 3b shows the same components as FIG. 3a. That is, the two filters include a resonator and a coupling structure. Because the diplexer uses a separate housing, there are also separate antenna ports 510a and 510b. Even if the TX band filter and RX band filter are built as two entities, they must be placed next to each other to form a diplexer function (see FIG. 3b) and again run on a common ground plane. It leads to coupling by fringe electric field and current. In an embodiment, these disadvantages can be overcome by separating the two filters 112, 122 by the PCB 100, ie by attaching the two filters 112, 122 on both sides of the PCB 100.

  If the filter is placed on the same side of the circuit board, perhaps on the same solder patch, the fringe field must be suppressed by complex means such as encapsulating the walls. This is expensive and does not fit the purpose of a highly integrated circuit. In embodiments, the filters can be placed on both sides of the circuit board. This allows the introduction of a separate ground plane that functions as a separating surface and shields the two filters from each other in a multilayer PCB. Thus, embodiments can allow a highly integrated radio structure to be configured, while maintaining high isolation between the two filters despite being close. Embodiments can overcome disadvantages resulting from costly, increased mechanical and circuit layout effort, such as box encapsulation.

  The description and drawings merely illustrate the principles of the invention. Although not explicitly described and shown herein, one of ordinary skill in the art appreciates that various arrangements can be devised that embody the principles of the invention and fall within the spirit and scope thereof. In addition, all examples detailed herein are, in principle, to assist the reader in understanding the principles of the present invention and the concepts provided by the inventor (s) promoting the technology, It is expressly intended to be for educational purposes only and should not be construed as being limited to such specifically detailed examples and conditions. Furthermore, in this specification, all statements detailing principles, aspects, and embodiments of the invention, and specific examples thereof, are intended to encompass equivalents thereof. It will be apparent to those skilled in the art that the block diagrams shown herein represent a conceptual perspective of an illustrative circuit that embodies the principles of the invention.

Claims (10)

  Print for forming a diplexer circuit including a first connector (110) for connecting the first filter (112) and a second connector (120) for connecting the second filter (122) A circuit board (100), wherein the first connector (110) and the second connector (120) are located on both sides of the printed circuit board (100), the printed circuit board being two non-conductive Further comprising two separated conductive layers (176; 178) between the substrate layer (132; 134) and the two non-conductive substrate layers (132; 134), the two separated conductive layers (176; 178) are separated by a separation layer (172), and the two separated conductive layers (176; 178) are parallel to form a waveguide structure, the waveguide structure Before A printed circuit board adapted to a quarter of the wavelength of the center frequency based on the transmission band determined by the first filter (112) and the reception band determined by the second filter (122) (100).   The printed circuit board (100) of claim 1, wherein the first connector (110) corresponds to a first solder patch and the second connector (120) corresponds to a second solder patch.   At least one connection or via (140) between the first connector (110) and the conductive layer (176; 178) and / or the second connector (120) and the conductive layer The printed circuit board (100) of claim 1, comprising at least one connection or via (142) between (176; 178).   The printed circuit board (100) of claim 1, wherein the conductive layer (176; 178) has a connector for grounding the conductive layer (176; 178).   The two conductive layers (176; 178) form protrusions around the connector (110) of the first filter (112) and / or the connector (120) of the second filter (122). The two conductive layers (176; 178) are connected through further connectors or vias (174) under the first and second connectors (110; 120), the protrusions being connected to the further connectors The printed circuit board (100) of claim 1, wherein the printed circuit board (100) extends from the via (174) or at least a quarter of a wavelength.   The printed circuit board (100) of claim 1, wherein the waveguide structure is adapted to guide the electromagnetic wave for at least a quarter of the wavelength of the wave. A method of manufacturing a printed circuit board (100) for forming a diplexer circuit comprising:
The printed circuit board comprising two non-conductive substrate layers (132; 134) and two separate conductive layers (176; 178) between the two non-conductive substrate layers (132; 134) Forming a waveguide structure in which the two separated conductive layers (176; 178) are separated by a separation layer (172) and the two separated conductive layers (176; 178) are parallel, the waveguide structure, a first transmission band determined by the filter (112), based on the reception band that is determined by and the second filter (122), the center frequency Adapted to a quarter of the wavelength of
Mounting a first connector (110) to connect a first filter (112) to a first side of the printed circuit board (100);
Mounting a second connector (120) to connect a second filter (122) to a second side of the printed circuit board (100), the first connector (110) and the A second connector (120) located on both sides of the printed circuit board (100).   The circuit board (100) of claim 1, a first filter (112) connected to the first connector (110) for filtering transmission signals in a transmission band, and a received signal in a reception band A diplexer circuit (200) including a second filter (122) connected to the second connector (120).   The first and second filters (112; 122) are further connected to an antenna using a first feed line (116) and a second feed line (126), and the first feed The line (116) and the second feed line (126) are located parallel to the printed circuit board (100), or the first and second filters (112; 122) are common The antenna circuit (160) is connected to an antenna, and the printed circuit board (100) connects the first and second filters (112; 122) to the common antenna port (160). The diplexer circuit (200) of claim 8, comprising a feed connector or via for connection.   Manufacturing a printed circuit board (100) for forming a diplexer circuit according to claim 7, attaching a first filter to a first connector, and attaching a second filter to the printed circuit board (100). Attaching the second connector to the diplexer.